1. Field
The present disclosure relates to a turbo generator powered by exhaust gas from an internal combustion engine.
2. Background
Electrical systems for motor vehicles have continued to evolve over the years. Today, these systems are often required to support an increasingly number of electrical components, such as servo motors, onboard computers, navigation systems, and entertainments systems, just to name a few. In addition, mechanical components, such as power steering pumps, air conditioning compressors, water pumps, oil pumps and other components traditionally driven by the engine's crankshaft, are more and more being electrically powered. As the demand for electrical power continues to increase, the use of traditional power generating means becomes less attractive. Not only in terms of physical size of the alternator required to meet this demand, but also in terms of additional fuel consuming load placed on the internal combustion engine at a time when fossil fuel is in short supply, the ecological consequences are great and the demand is for reduction in fuel consumption.
One possible solution is to generate electrical power from the exhaust gas energy of the internal combustion engine. A high-speed turbine mounted between the internal combustion engine and the exhaust system may be used to drive an electric generator. This solution may provide a number of benefits. For example, the fuel economy of the vehicle may be improved. The size of the crank shaft driven alternator may be reduced or the alternator may be eliminated, resulting in a reduction in engine fuel consumption and more compact and less expensive design. On hybrid vehicles, the turbine-driven generator may be used to supplement the supply of electric power for the electric drive system, reducing the on-time, and thus the filet consumption, of the internal combustion engine. In summary, all the electrical power generated by the turbo generator will result in a proportional direct reduction in engine fuel consumption.
Despite these benefits, it has proven to be difficult to integrate an efficient turbine-driven electrical generator in a motor vehicle. This is because conventional electric generators can deliver power only when operating within a specified speed range. The power delivered by a conventional electric generator falls off quickly when the operating speed exceeds the specified range, as is the case with the high rotational turbine speeds created by the internal combustion engine exhaust gas energy. As a result, this technique has not been applied widely to motor vehicles. The few applications that exist today are limited to large commercial vehicles (e.g., ships and large trucks) with a reduction gear mechanism at the output of the turbine to reduce the operating speed of the electric generator to the range required to produce power. This design requires a large space in engine compartment, making it unsuitable for standard passenger vehicles.
Accordingly, there is a need in the art for a system to generate electrical power from exhaust gas energy produced by an internal combustion engine suitable for standard passenger vehicle applications.